fuel psi on nos

[jaspermaggie]

I run an nso 100 shot what fuel psi do you use? I have set at 6 and does not hit as hard as I think it should I was thinking of 5.5. I am using 53F/47N It is on a 355 chevy plugs look good.

[John_Heard]

"Plugs look good" if indeed the tune up is spot on including timing it sounds like it's time to start turning it up. If you want to stick with a 100 shot then you might want to consider shortening the line lengths between the solenoids and that plate. That tends to make it it quicker.

[Scott Coxwell]

I have run the numbers and I think you have your jets in wrong. Smaller # jet should be on the fuel side and larger # on NOS side.

Here goes= with a 53 NOS jet and a 47 fuel jet you will have a Nitrous/fuel ratio of 6.05 with 99hp. Now lets change these to the way you have them in your car = with a 53 fuel and 47 NOS you then come to a nos/fuel ratio of 3.74 and my friend this is wayyy to low. Change the jets around set your flowing fuel psi to 6 "flowing" and go have fun. Hope I have been of some help..
Scott

[jaspermaggie]

That is what nos has 53f/47n for the 100 shot. I guess it is because it also states stock timing and plugs. It runs good but does not hit as hard as I remember. Car was out after braking driveshaft and trans. I also redid the fuel system. I think It was lean before. Does going from 6psi to 5.5 do much or would going dowm one fuel or up one nitrous. I hate to push it to much. I did a few calculators and all have 47n 43f for 100 shot but I asume I would need to take out 4 and one or two colder.

[John_Heard]

That won't run very good with those jets, it'll be pig fat like Scott said. If you want to be conservative try square jetting it at 5.5 psi - that's still fat but will be a lot better. NOS tune ups from the factory are waaaay off and super rich. What jets do you have to work with?

[jaspermaggie]

all the jets I have a bigger but I think I do have a 43 but to do that one I will need new plugs and go down in timing. I guess my problem is I drive it on the street most of the time. So I dont wont it to run like crap off nitrous, yes I wont it all. I dont wont a backfire so far so good, what power do you think it is making with the 53/47? Do you think I would be ok with stock with 47/47? I have an eddelbrock a/f what should I be looking for 12.5 or 13?

[Scott Coxwell]

Jet your nos bigger than your fuel side probably by 4 numbers. You need your timing to come out of it when it's activated only. try knocking out about 6 degrees and start from there. But you will need to be at the track to do some decent full throttle testing to confirm what the engine wants, Remember too much fuel is worse or as bad as too much NOS in the cylinders!!

[Scott Coxwell]

If I'm not mistaken I sent you a PM stating all your nos/fuel ratios and etc some time ago. Did you not get it?

[jaspermaggie]

no I did not but thank you anyway. I got an A/F and it is telling me I am low 12.5-13. I need 11.8. I am going to go up .5 psi and try that. I am getting a mallory 6 nitrous box soon and that will drop my timing. thank you